Is there a way to temporarily 'ignore' keyframes on a specific frame?
You can't disable them as such, but you can move them out of the way.

Select the keyframes you want to 'disable' and ensure the current frame is frame 0. Press S to Scale and type -1. This will scale using the current frame (zero) as the origin and swap the keyframe to the other side of the axis - so, for example, keyframes on frame 20 will be moved to frame -20. This will move them outside of the normal range of animated frames and effectively disable them (provided you have a keyframe at the start of the animation to set the initial state).

Enabled - the keyframe is in it's 'normal' position





Disabled - the keyframe has been moved to the opposite side of the axis





To 're-enable' the keyframes you can simply repeat the same action to mirror it back to the positive side of the axis (ie, frame -20 scaled by -1 becomes frame 20 again).